The present invention relates to a biaxial orientation blow molding machine and, more particularly, to a device for supplying a piece of cylindrical shape with a bottom and an open top or neck end, preformed by an injection molding machine, to a biaxial orientation blow molding machine.
In molding a bottle-shaped container of polyethylene terepthalate resin by means of an injection blow molding process, there is adopted an injection blow molding process which has the steps of first molding a cylindrical piece with a bottom by an injection molding machine, and then biaxial orientation blow molding the piece. Generally the injection-molded piece is cooled to a predetermined temperature by the difference of molding temperatures between the injection molding time and the blow molding time while the injection-molded piece is being supplied to the blow molding machine. The piece thus cooled is reheated to a predetermined temperature before the blow molding process.
The most advanced blow molding machine at present used consists of a heater and a blow molding machine asssembled integrally. In operation, the piece is assembled with a mandrel which is detached from a turntable, the mandrel with the piece is assembled with the turntable, and the piece is intermittently moved integral with the turntable in order to heat the piece to a predetermined temperature and execute the blow molding step.
It is required in such a blow molding machine to construct it so that it will rapidly and accurately assemble the piece to the mandrel detached from the turntable and assemble the piece with the mandrel from above due to the operational standpoint of the mandrel itself. In other words, it is required to supply the piece to the mandrel in an inverted attitude such that the opening of the piece is directed downwardly.
In the meantime, since the pieces are normally relatively small in size, a number of the pieces are simultaneously molded and are conveyed by a belt conveyor or the like without control of their attitude. If the attitude of the pieces is required to align and convey with their openings facing upwardly or downwardly, the pieces can be naturally stood normally by their own weight by engaging the necks of the pieces at a projected ledge peripherally provided therearound in case of the upward opening attitude, but it is impossible to convey the pieces in inverted attitude automatically because the shape and weight of the piece cannot be utilized automatically to invert the attitude of the pieces to a downward opening attitude.
Since the pieces can merely be conveyed at random in lateral attitude or in upward opening attitude though they must be assembled with the mandrel in downward opening attitude, they are assembled with the mandrel by manually inserting the pieces thus conveyed. Accordingly, the step of assembling the pieces with the mandrel is much lower in treating capacity than the other steps, thereby lowering the speed of the biaxial orientation blow molding process of a bottle-shaped container.